Short-term air pollution exposure aggravates Parkinson's disease in a population-based cohort

Increasing experimental evidence has suggested air pollution as new risk factor for neurological disease. Although long-term exposure is reportedly related to neurological disease, information on association with short-term exposure is scarce. We examined the association of short-term exposure to particles < 2.5 mu m (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O-3), and carbon monoxide (CO) with PD aggravation in Seoul from the National Health Insurance Service-National Sample Cohort, Korea during 2002-2013. PD aggravation cases were defined as emergency hospital admissions for primarily diagnosed PD and analyzed with a case-crossover analysis, designed for rare acute outcomes. Pollutants concentrations on case and control days were compared and effect modifications were explored. A unit increase in 8-day moving average of concentrations was significantly associated with PD aggravation. The association was consistent for PM2.5 (odds ratio [95% confidence interval]: 1.61 [1.14-2.29] per 10 mu g/m(3)), NO2 (2.35 [1.39-3.97] per 10 ppb), SO2 (1.54 [1.11-2.14] per 1 ppb), and CO (1.46 [1.05-2.04] per 0.1 ppm). The associations were stronger in women, patients aged 65-74 years, and cold season, but not significant. In conclusion, short-term air pollution exposure increased risk of PD aggravation, and may cause neurological disease progression in humans.